avilla20

so lately ive been noticing my coolant level going down slowly after a couple days like only a 1/4in at a time over a couple days, i always check it when its cold in the morning and i add like 1/4in of coolant if its at the cold mark, then over a couple days itll be back down at cold, after driving at times i open the hood and use an infered temp gun to check temp(temp gauge no worky) and its never over 240 even if im on it on a 100 degree day, but i have noticed coolant leaking out of the over flow bottle neck at the top, i tried to tighten the lid but it only pops and losens up agin, so i checked the thread and found the plastic neck thread broken half way up the neck so i put silicone to try to seal it up and drove it hard, but it didnt work. what im worried about is that im used to working on sealed degass bottle systems on newer cars that only purge coolant out of the over flow cap if the cap is bad or a head gasket is blown, but on this style it would boil out the radiator cap right?so i was just wondering if this indicated a problem with the engine or the over flow bottle is just not sealing and losing coolant out the top? is the engine fine and not worry about it...besides losing a litle coolant? added pic.of wat it looks like after driving.

camaronewbie

As I've always understood it, our systems are 'sealed' in a sense, but the overflow tank is not a part of the 'sealed' system. The radiator cap seals the system, and are designed to release this 'seal' at 16psi - when things get too hot, the pressure builds, and above 16psi the rad cap allows the excess to run to the overflow tank.

Your cap on the overflow tank only serves the purpose of keeping the fluid in there from splashing out on bumps, cornering, etc. - its not supposed to be airtight.

BUT - if it's leaking like that regularly, unless your doing some serious 4 wheeling, I'd think that you are overheating, and you should check into that ASAP. I've never even seen my level change between cold and 220 (I never get above 220), and I'm running a much smaller overflow tank (not factory). I wouldn't think a 3rd gen could bounce around enough to make enough coolant leak from that cap to make a stain like that.

Get that temp guage working.
Find out why you are running so hot.
That bottle cap can be bought at any auto parts store - look in the HELP! section.

white gold 88

Had the same problem. Found the leak in the bottom of the coolant jug.

naf

iTrader: (7)

Replace your radiator cap. It costs like $3. When it fails it will allow the coolant to boil over into the overflow bottle before the engine is overtemp.

A new bottle can be had from modern day muscle shipped for like $20-25

avilla20

well i figured if i was over heating, coolant would purge out of the radiator cap and make a huge mess, and when its cold the coolant is at cold and when its at 220 its not over hot, but somtimes it's under the hot mark, idont belive im overheating, if i drive in traffic and pull over and check with gun itll be around 220-228 and the fan will kick on and lower it to200-210 after a min of idleing, i would also imagine coolant would drip onto the ground if it was oveheating but it doesnt, and i replaced the rad cap like 3months ago with a 13psi cap( what napas book said on both my camaros so they both got 13) and the bottle cap isnt broken its the neck.

avilla20

pic to help clarify broken neck...

naf

iTrader: (7)

It shouldn't be filling the overflow bottle enough to lose that much at the cap. The overflow bottle should have a cold fill line and a hot fill line. If you're putting too much into the overflow bottle it WILL leak out.

avilla20

no when its cold its at cold and when its hot its at hot, after a couple days its a tiny bit under cold in the morning before starting thats when i add only a tiny bit.

sonjaab

If its blowing coolant out of the top of the overflow bottle you have either
a overheating , headgasket/intake pressure, radiator cap problem !

A pressure test and inspection is in order !

My overflow bottle cap top is stripped like yours and does NOT puke
coolant out of the top!

avilla20

ok well this is were im at. i got the car 5 monts ago and had a water pump and heater core leak, replaced both and thermostat, and after that coolant would puke out of radiator cap once engine got hot so i thought it was a head gaset leak and had a co-worker sniff the coolant with the smog machine at the radiator neck and it passed, and found the radiator cap was shot, replaced it with a 13psi cap from napa and fixed the purging from rad cap. t-stat housing has a small leak at the base were it curves up, so that needs fix,and its not over heating, like i said wen i pull over when hot itl be at 230 with gun and drop to 210-220 with fan but since my temp gauge isnt working i dont know what its doing under accel and load so it might be a possible. and the new cap might be off a bit by a couple pounds, will check cap tomorrow. but what is the normal temp for a 305tpi? and if it was a head gasket wouldnt it purge from rad cap...right?

sonjaab

NO...................That is the purpose of the overflow bottle.
It should never leak around the base of the radiator cap. If the cooling
system is over pressurized the excess pressure/coolant/steam should flow/
vent into the overflow bottle.

If the overflow is excessive and occurs all the time there is a problem in
the cooling system or engine.

avilla20

ok so did some work today on the ROC. i started by testing the rad cap, i can pressurize it to 16 and it holds and to 17 and it holds once it gets to 18psi it releases and drops to 13 or 14psi and holds, then pressure tested cooling system to 18psi and held. so i think i might replace the cap just for s**** and giggles.

then i went after the gauge.the gauge since i got has been pegged out
passed 260 as far as it can go key on or key off.so i used one off a 84 z28 and did same thing so i put the original back in and move the needle to cold and turned the key on and bam pegged as far as it can go and did not come down no matter what i did. so i decided to map out temp sender to make sure it wasnt shorted,i disconnected the sender and put my red dmm lead on the sender and black lead on the battery ground and i found it was a ntc thermistor. at 80 degrees it was at 2.156kohms, and at 100 degrees at 1.2-1.3kohms and went down as temp went up i let the car warm up in my drive way and idle for 30 min while maping the senderat 230degrees it was at 120ohms and 160ohms at 215 degrees with the lowest ohms being 105ohms at 242 degrees. so according to the wiring diagram i have the sender is right in the range.

and while i was doing all this testing i was also checking thermostat op and fan op and kept an eye on the over flow bottle. measured differance from t-stat housing and upper radiator hose in let at radiator while warm up and and found when the tstat was at 190 the rad was at 180 and then got up to 190 and then both got to 200 around the same time and around 210 the overflow started to fill, and the were a few bubbles in the coolant as it was filling but i think thatwas normal, and once the upper radiator hose was hot and fully pressurized the overflow stopped filling and never went over the hot line. the highest temp i saw was 240-245degrees and the fan would kick on around 241 degrees and dropped to 215-218 degrees when fan kicked off and would climb back up to 238-240 after 5-10 min and drop back down again. while doing all of this i never got steam,boilng/bubbling,areated coolant from the over flow bottle. i held it at 3000rpm for a good while and it didnt go over 240 and didnt do anything to over flow bottle.

avilla20

so i shut the engine down and and went after the sending unit wiring probably shorted to ground, with it disconnected from sending unit i put my dmm red lead on the connector on the dark green wire and my black lead on battery and checked continuity to ground and got 82ohms...way to much so i figured its short to ground,theres no way it should be getting ground with key off, so i wiggled harness up to the point were it goes behind the engine and got no change.i ran out of day light so i stopped, i plan on chasing it tomorrow so i just wantted to ask some questions. because i wanna chase the short from the sender to dash. and in the wiring diagram shows to connectors before cluster the first has no number? and the second is called c100, i plan on disconnecting one by one to see if short goes away, so ill just over lay it to that connector and not all the way to the cluster. so doea anyone know were c100 is located and wat the connector face looks like and how its pinned?

avilla20

the wiring diagram im using

deadbird

*edit: nvm.....

avilla20

any ideas on c100 and the other connector?

camaronewbie

The c100 connector is the big one driver side firewall beside brake booster - it's the main wire harness connector between inside and outside of car.

Sounds like everything except the guage is working correctly - but those temps are a little hot for my liking. I'd get a 180 stat if you don't already have one, and get a lower temp fan switch to cut fans on earlier.

sonjaab

Does your heater put out hot air?

If not then your thermostat is not opening and causing the overheating/coolant
boiling/puking.

Then that is causing your problem.

Maeryk

I replaced the heater core in my V6.. it ran fine for a day, then barfed what looked like half the rad. I refilled it, checked for leaks, never had another problem. It also did that when I replaced the alternator..

It's possible you just had a big air bubble in the system that caused it spew. Has it happened more than once?

avilla20

do you have a connector face or pin diagram for c100.and i got a 190 t stat and i thought these temps were normal for these engines to run hot. but i plan on trying a 180 down the road.

not sure i replaced it at the beginning of summer and havent checked it since its hot outside all the time,so running the heater isnt a good idea and i think my tstat is opening since i can monitor the temp difference between tstat housing and radiator drop as it warms up and both completely equalize at 200degrees
it happens every other time i drive it, and engine bay smells like coolant, cant find any leaks except the over flow bottle.

Maeryk

When you fill it, do you let it run till the thermostat opens, the level drops, and then top it up with the cap off?

Any time it vents into the bottle, even if it doesn't splash out, you are going to smell coolant.

Pull the radiator cap (car cold). Start the car, and watch the level in the rad. When the thermostat opens, it should suck in a bunch more from the radiator. Have the heater on "hot" just to make sure you have coolant running into ALL the possible lines. as it's running, watch the level, and top up. it might burp some as the thermostat opens, but after that initial "bubble" it should suck in to full cap in the motor and heater core. As with all things.. don't put your face directly over the hole!

Once it's up to level, put the cap on, shut the car off, and let it cool. Recheck level when it's cool.

oh, and don't open it hot. I lost the cap on my dodge 400 that way. It went lord knows where, but we never did find the durn thing.

avilla20

that was the way i bleed the system when did the thermostat, then the water pump, and again when i did the heater core.

well i believe that i have proven out the circuitry from the cluster to the temp sender, i have 12v to the gauge itself, so im going to try a different gauge and if that doesnt work the a new cluster will be at hand.

so i talked my issue over with the master tech work and he said that eventhough the smog machine didnt pick up any hc's i might have a bad head gasket due to my engine runs rough in the morning and blows a bit of smoke on initial start up, so he told me to take out all spark plugs and pressure ize cooling system over night and see wich cylinder has coolant in it, so ill be trying that in two weeks due to time.

ASE doc

Your rad cap needs to be 16 psi. If NAPA's "book" said its 13 psi, they were reading the "book" wrong. Too low of cap pressure will allow too much coolant to pass into the reservoir, causing your overflow. It will also allow the coolant to boil in the engine, causing high cyl head temps. High head temps are not good. Every pound of pressure increases boiling temp 4 degrees. 16 psi increases boiling point from 212 to about 276. This high boiling point is essential in any engine running a 194 degree t-stat and 220-240 degree operating range.

avilla20

yea sorry about that it is actually a 16psi cap and releases above 17psi....got it confused with a different car.

ASE doc

One thing to point out. Take care when performing the test recommended by your master tech. A large quantity of water in a cylinder will cause a pressure spike when the engine is turned over at cranking speed even with the spark plugs removed. The safest way to perform this test is using a breaker handle to slowly turn the engine over after sitting for some hours with the cooling system pressurized. Have an assistant turn the crank while you watch for water to eject from a spark plug hole. Using the starter to turn the crank when a cylinder has filled with water can easily result in a bent rod.

Also, steam from your exhaust on start up is normal on any catalyst vehicle. The catalytic converter produces steam as it heats up. The more CO it has to process as the engine cycles through warm up enrichment, the more steam youll see. The rough idle when cold can easily be caused by injectors or engine tune. A failed head gasket will generally cause bubbling in the coolant reservoir and Ive yet to see a failed head gasket that didnt induce HC in the coolant gases.

avilla20

ok so i took out my spark plugs today and inspected them...none look like they have been burning coolant, they all just look really old(may be original) and worn out.i added pics, i dont think im going to pressurize cooling system over night i figure if head gasket was leaking spark plugs would be stained and showing. what do you guys think? should i pressurize and check? do these plugs look like they have been in coolant? ...pics....

naf

iTrader: (7)

I'd have to see them up close but your timing may be a little advanced and you may need to go up a plug in heat range.

But they really don't look bad.